464 IX. CAROTENOIDS AND VITAMINS A 



have higher blood levels. This sex variation is corroborated by the exten- 

 sive data on the basis of which a sex variation in plasma vitamin A has also 

 been established. In the latter case, the situation is reversed, i.e., higher 

 plasma vitamin A values are noted in men than in women. 



Parturition is a phenomenon which is associated with marked variations 

 in blood carotene in cows. Sutton et al.^" reported a sharp decrease in 

 blood carotenoids immediately after the birth of the calf, with a slow re- 

 covery occurring over the subsequent fourteen to twenty-one days. Good- 

 \\in and Wilson ^'^ have confirmed these results, although they related these 

 changes to the general alterations in the blood during this period. 



Season is another factor which can be correlated with changes in the caro- 

 tene content of the blood of cattle. The effect in this case is apparently in- 

 direct, due to the fact that the quantity of available carotenoid-containing 

 foods varies at different times of the year. Thus, Brami-^^ reported a max- 

 imum level of 1350 ng. % of plasma carotenoids in the blood of Holsteins 

 when they were on green pasture in March, while the minimum figure of 

 280 ug. % was observed in the October samples when green feed was not 

 available. Similar variations were noted in Lord^^^ for Ayrshire cows. 

 Seasonal variation in the availability of green foods may result in variations 

 in blood carotene not only in the case of cattle but also in that of children ; 

 this is indicated by the results of Szymanski and Longwell,^"- who reported 

 average figures of 152 ug. % for the summer period (June to November) 

 and 132 fxg. % for the winter months (December to May). 



Certain miscellaneous dietary constituents may also cause variations in 

 blood carotene. Thus, the administration of mineral oil concomitantly 

 with carotene causes a decrease in the level of blood carotene, ^^■^^^•^-° 

 presumably as a result of the reduced absorption of the provitamin A un- 

 der these conditions. Sulfonamide therapy was found by Ronning and 

 Knodt^^^ to be A\dthout effect on the level of plasma carotene. Dietary 

 penicillin was reported by Burgess et al.^^^ to cause a significant rise in 

 plasma carotenoids in the chick. 



(c) Pathologic Factors. In the case of human subjects, pronounced 

 variations in the values of blood carotene may obtain which are not as- 

 sociated with a corresponding alteration in intake or with other physiologic 

 factors. 



Diabetes mellitus is the classical disease in which carotenemia has fre- 



"' T. S. Sutton, H. E. Kaeser, and P. A. Solclner, /. Dairy Set., 28, 933-939 (1945). 



3'8 T. W. Goodwin and A. A. Wilson, Biochem. J., 49, 499-503 (1951). 



319 J. W. Lord, Biochem. J., 39, 373-374 (1945). 



'20 A. C. Curtis and E. M. Kline, Arch. Internal Med., 63, 54-63 (1939). 



321 M. Ronning and C. B. Knodt, J. Dairy Sci., S3, 424-429 (1950). 



